1. Field of the Invention
The present invention relates to the field of photography and, more specifically, to photographic apparatus utilizing modular construction techniques.
2. Description of the Prior Art
The current state of the art in "one-step photographic systems" features integral or "nonpeel-apart" self-developing film units and highly-automated cameras for exposing and processing these film units.
In a typical battery-operated camera, a film container holding a plurality of self-developing film units is inserted into the camera-receiving chamber. In response to closing a film loading door, on the camera, an electrical switch is closed causing the camera to operate in a preexposure mode whereby a dark slide covering the forwardmost film unit in the container is advanced from the container and is at least partially ejected from the camera.
To take a picture, the user frames the subject with the viewfinder, focuses the objective lens, and activates a cycle-start button on the camera housing. The operating cycle includes the steps of exposing the forwardmost film unit under the control of a light-sensing exposure control circuit; advancing the exposed film unit from the film container to a processing station which includes a pair of pressure-applying rollers; transporting the film unit between the rollers to distribute a fluid processing composition between predetermined layers of the film unit; at least partially ejecting the film unit from the camera; resetting the operating mechanisms within the camera for the next cycle of operation; and terminating the operating cycle. If the camera is of the reflex-viewing type, the cycle includes the additional steps of converting the optical system from a viewing mode to an exposure mode and the subsequent reset of this subsystem.
The complete operating cycle may take as little as 1.5 seconds. However, the cycle time is not fixed because the exposure interval will vary in a dependent relationship to the intensity of scene lighting conditions. In order to coordinate the occurrence of the camera functions outlined above, some type of sequencing system is required.
The prior art is replete with cameras having operating mechanism for initiating, controlling and/or performing all or some of the enumerated functions comprising an operating cycle. Representative examples of such camera may be found in U.S. Pat. Nos. 3,683,771; 3,714,879; 3,744,388; 3,757,657; and 3,826,655.
The above disclosures describe various camera operating mechanisms mainly from a functional standpoint with little information as to a practical embodiment that is specifically designed to be easily manufactured at a low-cost and in large volumes.